Delta Air Lines plans to reduce the number of 50-seat regional jets that it contracts with regional carriers to 125, if its Air Line Pilots Association-represented pilots ratify a new labour contract.

The Atlanta-based airline would replace 218 of its current 343 50-seat RJs with 70 76-seat RJs at its existing regional carriers, according to a Negotiators’ Notepad from the union. Comair, Pinnacle and its subsidiary Mesaba, and SkyWest and its subsidiary ExpressJet Airlines currently operate the smaller jets for Delta.

“[Delta] is seeking to substantially reduce the number of 50-seat aircraft operated by its DCI [Delta Connection] carriers, as quickly as possible,” wrote the Delta master executive negotiating committee in the notepad.

The deal, which is dependent on Delta completing its acquisition of 88 Boeing 717-200s from Southwest Airlines subsidiary AirTran Airways, would result in a net reduction of 60 aircraft from Delta’s combined mainline and regional fleet.

Delta declined to comment on the tentative agreement until after the ratification process.

The airline’s pilots are scheduled to vote on the tentative agreement later this month.

Delta’s existing regional partners are expected to operate the new 76-seat aircraft. The airline has options for 36 Embraer 175s with delivery dates between 2013 and 2015, according to Flightglobal’s Ascend database. These aircraft would likely be flown by the carrier’s Comair subsidiary.

Embraer previously told Flightglobal that it would confirm a deal for the 175 before American Eagle emerges from bankruptcy, which is expected in the fourth quarter.

ExpressJet or SkyWest, which currently operate CRJ900s for Delta, are the likely operators of the remaining 34 76-seat jets. Bombardier would be well placed to win the order for these aircraft based on the carrier’s current fleets

Pinnacle plans to shed its existing CRJ900 aircraft in favour of an all 50-seat CRJ200 fleet operated under contract with Delta, as part of its reorganisation under chapter 11 bankruptcy protection.